Micro-SD Cards Compared

Of course, there are great smartphones with large memory. But, it is cheaper to buy a model with memory card slot and separately a micro-SD card. However, where the offer is more than confusing. Connect has tested the most popular cards and explains what to look for when purchasing.

If you buy cheap, buy twice – that is a warning to reckless bargain hunters. But smartphones be taken related to memory. At first glance, it can be useful to buy is a smart phone with oversized storage? 110 euros demanded about Apple in September 2016 for the memory from 32 to 128 gigabytes at the iPhone 7 converted to a 64 GB card 73 euro, street prices for corresponding micro SDs begin, however, already less than 20 euros. Particularly strong is the price difference for people in the weight, which often change the Smartphone. Because a memory card like makes the switch, built-in storage juicy charges again.

But what card take, with street prices ranging up to almost 200 euros for a professional, super fast 128-gigabyte model from around 20 euros for a standard micro SD 64 gigabytes? We have tested cards from Lexar, Kingston, Samsung, SanDisk and transcend. Some differences can be seen already in the Declaration. Here is the so-called speed class the oldest. It stands as a number with a C on the map, C2, C4, C6, C8, and C10 are possible. The number indicates the write speed in megabytes per second (MB / s). With only the top class is common and all test cards significantly exceed 10 MB / s.

UHS classification

The UHS (ultra high speed), classification clearly displays a U with number higher speeds. U1 stands for at least 10 MB / s, U3 for 30 MB / s and more. In the benchmarks with U3 classified test cards cut reliable performance than counterparts U1. For 28 euro priced piercing out for 64 gigabytes, the SanDisk here is extreme with 292 points.

Because the interface on which communicates the map with other devices, slows down the speed of modern memory cells, there is a second transfer bus for fast cards. Whose connections are in a second row parallel to the standard ports. The new bus is called UHS-II and is documented by a Roman two on the map. Conventional cards are often declared UHS-I-cards with a Roman one, slow cards the UHS reference is missing entirely.

Since UHS-II card UHS-I connectors, they are backward-compatible. But to their increased speed use to enable a, it requires a UHS-II-capable partner. Therefore, Lexar and SanDisk deliver their UHS-II cards with a card reader, Lexar a SD card adapter for the high speed. In addition, there are also some very high-quality cameras with UHS-II interface. The standard is so far not implemented for smartphones. Therefore the purchase worth more as an investment in the future – or when data is often transmitted over appropriate card reader should be. Speaking of future: the comparatively high price of SanDisk Extreme Pro cards can be explained also by a 30-year extended warranty.

This is noteworthy as not as often to write to the Flash memory in micro-SD cards. Because each write operation the oxide layer is damaged a little, prevents that stored information from the memory cell is discharged as a charge.

Depending on the technology, expect up to a million write operations by 100,000. That sounds like a lot. But each store requires write access on a table, holding, where what is. Circumstances this at a fixed point, 100,000 write operations would be quickly reached, why the optimized card controller write operations distributed as evenly as possible on the whole memory area, so that each cell is similar to frequently used.

In the test procedure evaluates connect at the facilities in addition to the capacity offered per euro, also offerings such as an SD card adapter and card reader.

Under measurements, the data transfer rates and access times are assessed. Here, the UHS-II cards Lexar professional and SanDisk were clearly extreme Pro UHS-II front.

But in the Smartphone are the best UHS-I cards as quickly–here can convince the affordable Kingston SDCAC, the transcend ultimate, and particularly the SanDisk Extreme as alternatives.